In collaboration with Drs. John Robbins and Rachel Schneerson at the Laboratory of Developmental and Molecular Immunology of the NICHD, we have developed a candidate conjugate vaccine that consists of Pfs25-Pfs25 conjugates. The immune sera induced by the conjugate vaccine displayed ability to block parasite development in mosquitoes. An Investigational New Drug Application was filed with FDA, intending a Phase 1 trial to test the safety, immunogenicity, and ex-vivo transmission blocking activity in humans. In response to FDAs comment, additional animal studies were conducted to evaluate the safety in animals.